LITHO-MAGNETIC AND STRUCTURAL MAPPING FROM INTERPRETATION OF HIGH RESOLUTION AEROMAGNETIC DATA OVER NORTHERN BIDA BASIN AND ENVIRONS NORTH-CENTRAL NIGERIA

Abstract

Recently, the Nigerian Geological Survey Agency (NGSA) acquired high resolution airborne
data over Nigeria and have commenced surface geological mapping in some parts of the
country. This research becomes imperative taking into account time consumption and the risk
associated with geological field mapping in recent time which includes difficulty in terrain
coverage, abduction of field workers and insurgency in some part of the country. In this
research an attempt was made to carry out litho-magnetic mapping and delineation of surface
structures from interpretation of high resolution aeromagnetic data within northern Bida basin
and environs. High resolution aeromagnetic data of the study area was subjected to regional
residual separation, analytical signal, vertical derivative, tilt angle derivative, horizontal tilt
derivative and upward continuation filters in the Oasis Montaj Version 7.0.1 Geo-software
environment to enhance data for interpretation. Results from the total magnetic intensity
(TMI) and residual data shows that magnetic intensity values range from 33,961.54 nT to
34,124.84 nT and -37.75nT/m to 124.08 nT/m respectively. Results of litho-magnetic
mapping on the basis of magnetic susceptibilities helped in demarcating lithologies
associated with Basement Complex and sedimentary terrains. Structures mapped in the study
area are faults which trends in the NE-SW and NW-SE dominant directions and other minor
direction are in the E-W. These results put together assisted in the preparation of a
comprehensive litho-magnetic and structural map of the study area.